Session K28 - Clusters: Nanophase and Supported.
MIXED session, Wednesday afternoon, March 19
Room 4300E, Conv. Center
New measurements of I(V,z) from nanometer-size crystalline Au clusters using an UHV STM are reported. In contrast to previous studies,[1,2,3] Au clusters are now encapsulated by dodecanethiol molecules. After encapsulation, the clusters are deposited on either a freshly cleaved MoS_2 substrate or on a Au(111) film coated with a self assembled monolayer (SAM) of a double ended thiol, p-xylene-\alpha,\alpha'-dithiol (C_8H_10S_2 ). STM images of the encapsulated clusters supported on either substrate reveal a regular, hexagonal closed packed array. I(V,Z) data obtained from isolated clusters exhibit reproducible single electron tunneling behavior. By using the same STM tip, the size dependence of the single electron tunneling features in the I(V,z) data can be studied reliably. By fitting the measured I(V,z) data to the semiclassical theory for Coulomb blockade, the electronic properties of the tunnel junction between cluster and substrate can be determined.
\vspace11pt [1]. M. Dorogi, et al., Phys. Rev. B52, 9071 (1995).
[2]. R.P. Andres, et al., Science 272, 1323 (1996).
[3]. Samanta, et al., Phys. Rev. B53, 7626 (1996).